The sense of sight is utterly compelling to those human beings who possess it. The adage that a picture is worth a thousand words resonates with an appreciation of the profound importance of taking in visual information. The sense of sight is unique in allowing us to absorb so much information from our world so quickly. It is natural then that advertisers, entertainers, artists, and others all want to engage people with their own visual content for the purpose creating a desired response in their intended audience. A large scale visual display system is a particularly compelling way for people to experience the presentation of visual information and such systems are the focus of the present disclosure.
There are numerous features of a visual display system that contribute to its impact upon viewers including: size, brightness, contrast, color saturation, color depth, display refresh rate, resolution, pixel pitch, pixel pitch uniformity, and others.
There are numerous other features of a visual display system that are of interest to the owners and operators of such systems including: ease of installation, ease of service, reliability, ease of configuration, ease of maintenance, ease of operation, cost of the system, cost of installation, cost of operation, cost of service, and others.
Display systems with large screen sizes present a number of difficult problems that are in need of solution. One significant challenge for display owners and operators is to maintain the visual performance of a large display once it has been installed in a viewing location. The visual performance of a display can be characterized using a number of measures including: uniformity of brightness across the entire display, uniformity of color across the entire display, contrast ratio, color temperature and uniformity of color temperature across the entire display, color fidelity to predetermined standards, etc.
Large displays may be built from a plurality of individual light emitting elements, arranged in a pre-determined pattern to create a composite viewing plane. Due to variances in manufactured materials and manufacturing processes, it is a fact of life that characteristics of individual light emitting devices vary from one device to the next and that individual devices may respond differently to environmental conditions of voltage, current, temperature, humidity, exposure to sun light, exposure to atmospheric gases such as ozone and nitrogen oxides, and aging. Variations in performance of individual light emitting elements include the characteristics of: luminous intensity per light emitting element, luminous intensity produced per unit current, dominant wave length of emitted light, wavelength distribution of emitted light, temperature coefficient of change of any of the prior parameters. Visual performance of the entire display is therefor subject to change as each and every light emitting element is exposed to the previously listed environmental factors and their variations over time.
In consideration of the foregoing points, it is clear that embodiments of the present disclosure confer numerous advantages and are therefore highly desirable.